Discovery [1] | |
---|---|
Discovered by | J. Chacornac |
Discovery date | October 28, 1854 |
Designations | |
(33) Polyhymnia | |
Pronunciation | /pɒliˈhɪmniə/ [2] |
Named after | Polyhymnia |
A887 HA; 1938 FE; 1953 AK; 1957 YL; 1963 DG; 1976 YT7 | |
Main belt | |
Orbital characteristics [3] | |
Epoch April 18, 2013 (JD 2456400.5) | |
Aphelion | 573.518 Gm (3.83373 AU) |
Perihelion | 284.409 Gm (1.90116 AU) |
428.964 Gm (2.86745 AU) | |
Eccentricity | 0.33698 |
1,773.541 d (4.86 a) | |
256.476° | |
Inclination | 1.869° |
8.595° | |
338.123° | |
Physical characteristics | |
Dimensions | 54.39±11.84 km (infrared) [4] 53.98±0.91 km [5] 64±6 km (occultation) [6] |
18.60888±0.00029 h [7] | |
S [3] or Sq [8] | |
8.55 [3] | |
33 Polyhymnia is a main belt asteroid that was discovered by French astronomer Jean Chacornac on October 28, 1854 [1] and named after Polyhymnia, the Greek Muse of sacred hymns.
Photometric observations of this asteroid at the Organ Mesa Observatory in Las Cruces, New Mexico during 2008 gave a light curve with a period of 18.609 ± 0.002 hours and a brightness variation of 0.15 ± 0.02 in magnitude. This result is in good agreement with a previous study performed during 1980. [9] These results were re-examined with additional observations in 2011, yielding a refined estimate of 18.608 ± 0.001 hours and a brightness variation of 0.18 ± 0.02 magnitude. [10] In 2020, an analysis of photometric data of Polyhymnia from 2008-2019 determined a more precise rotation period of 18.60888±0.00029 h. Two possible north pole orientations of Polyhymnia were also determined, with both solutions indicating an axial tilt of 151–155° (ecliptic latitudes –61° to –65°) with respect to the ecliptic. [7]
On its highly eccentric (0.338) orbit around the Sun, 33 Polyhymnia appears brightest (apparent magnitude 10) at its minimum distance from Earth of 0.91 AU. [11] Its orbit puts it in a 22:9 mean-motion resonance with the planet Jupiter. The computed Lyapunov time for this asteroid is 10,000 years, indicating that it occupies a chaotic orbit that will change randomly over time because of gravitational perturbations of the planets. [12] Measurements of the position for this asteroid from 1854 to 1969 were used to determine the gravitational influence of Jupiter upon 33 Polyhymnia. This yields an inverse mass ratio of 1,047.341 ± 0.011 for Jupiter relative to the Sun. [13]
In 2012, a study by Benoît Carry gave a meta-estimate of a mass of (6.20±0.74)×1018 kg for Polyhymnia, based on a single study of its gravitational influence on other Solar System bodies. [5] However, given Polyhymnia's diameter of 54 km (34 mi), this mass implies an extremely high density of 75.28±9.71 g/cm3. Such a high density is unrealistic, so this mass and density estimate of Polyhymnia was considered unreliable by Carry. [5] Several other asteroids with diameters similar to Polyhymnia were also measured to have extremely high densities in Carry's study, and were rejected for being unrealistic. [5] Because of Polyhymnia's small size, its gravitational influence on other bodies is extremely difficult to detect and may lead to highly inaccurate mass and density estimates. [5] For example, the 68 km (42 mi)-diameter asteroid 675 Ludmilla was originally measured to have a density of 73.99±15.05 g/cm3 in Carry's study, [5] but improved orbit calculations in 2019 showed that it had a much lower density of 3.99±1.94 g/cm3. [14]
No other peer-reviewed study has attempted to determine a mass and density for Polyhymnia since Carry's study, [15] though in 2023, researcher Fan Li performed a preliminary analysis of Polyhymnia's close approaches with other asteroids and determined a lower mass of (1.03±0.40)×1018 kg. [16] Depending on the diameter used for Polyhymnia, this mass estimate suggests a density of 7.5±3.6 g/cm3 or 12.4 g/cm3, for an occultation-derived diameter of 64 ± 6 km (39.8 ± 3.7 mi) and infrared-derived diameter of 54 km (34 mi), respectively. [16] [17]
Visible light spectroscopy of Polyhymnia from 1995 and 2002 show that it is an S-type asteroid, meaning it is mainly composed of rocky silicates. [3] In particular, Polyhymnia's spectrum exhibits an absorption band at 0.67 μm wavelengths, which indicates olivine and pyroxene on its surface, similar to Q-type asteroids. [8] : 155, 164–165 Since Polyhymnia shares both characteristics of S- and Q-type asteroids, it is further classified as an Sq-type asteroid according to the SMASS classification. [8] : 155, 164–165 Radio telescopes have studied Polyhymnia by radar in 1985. [18] [19]
In 2023, researchers Evan LaForge, Will Price, and Johann Rafelski speculated the possibility that Polyhymnia could be composed of high-density superheavy elements near atomic number 164, if Polyhymnia's extremely high density were correct and superheavy elements could be sufficiently stable. [20] However, as noted above, Polyhymnia very likely does not have such a high density. [16] [17]
624 Hektor is the largest Jupiter trojan and the namesake of the Hektor family, with a highly elongated shape equivalent in volume to a sphere of approximately 225 to 250 kilometers diameter. It was discovered on 10 February 1907, by astronomer August Kopff at Heidelberg Observatory in southwest Germany, and named after the Trojan prince Hector, from Greek mythology. It has one small 12-kilometer sized satellite, Skamandrios, discovered in 2006.
11 Parthenope is a large, bright main-belt asteroid.
36 Atalante is a large, dark main-belt asteroid. It was discovered by the German-French astronomer H. Goldschmidt on October 5, 1855, and named by French mathematician Urbain Le Verrier after the Greek mythological heroine Atalanta. It was rendered 'Atalanta' in English sources in the 19th century. This asteroid is classified as C-type (carbonaceous), according to the Tholen classification system.
41 Daphne is a large asteroid from the asteroid belt. It is a dark-surfaced body 174 km in diameter is probably composed of primitive carbonaceous chondrites. The spectra of the asteroid displays evidence of aqueous alteration. It was discovered by H. Goldschmidt on May 22, 1856, and named after Daphne, the nymph in Greek mythology who was turned into a laurel tree. Incorrect orbital calculations initially resulted in 56 Melete being mistaken for a second sighting of Daphne. Daphne was not sighted again until August 31, 1862.
46 Hestia is a large, dark main-belt asteroid. It is also the primary body of the Hestia clump, a group of asteroids with similar orbits.
49 Pales is a large, dark main-belt asteroid. It was discovered by German-French astronomer Hermann Goldschmidt on 19 September 1857 from his balcony in Paris. The asteroid is named after Pales, the goddess of shepherds in Roman mythology. Since it was discovered on the same night as 48 Doris, geologist Élie de Beaumont suggested naming the two "The Twins".
50 Virginia is a large, very dark main belt asteroid. It was discovered by American astronomer James Ferguson on October 4, 1857, from the United States Naval Observatory in Washington, D.C. German astronomer Robert Luther discovered it independently on October 19 from Düsseldorf, and his discovery was announced first.
53 Kalypso is a large and very dark main belt asteroid that was discovered by German astronomer Robert Luther on April 4, 1858, at Düsseldorf. It is named after Calypso, a sea nymph in Greek mythology, a name it shares with Calypso, a moon of Saturn.
57 Mnemosyne is a large main belt asteroid. It is a stony S-type asteroid in composition. This object was discovered by Robert Luther on 22 September 1859 in Düsseldorf. Its name was chosen by Martin Hoek, the director of the Utrecht Observatory, in reference to Mnemosyne, a Titaness in Greek mythology.
84 Klio is a fairly large and very dark main-belt asteroid. It was discovered by R. Luther on 25 August 1865, and named after Clio, the Muse of history in Greek mythology. The name Clio had previously been suggested by the discoverer of 12 Victoria, and that is the name B. A. Gould, editor of the prestigious Astronomical Journal, adopted for that asteroid, because of the controversy over the name Victoria. An occultation by Klio over a dim star was observed on 2 April 1997.
175 Andromache is a main-belt asteroid that was discovered by Canadian-American astronomer J. C. Watson on October 1, 1877, and named after Andromache, wife of Hector during the Trojan War. Watson's telegram to Europe announcing the discovery became lost, and so notification did not arrive until several weeks later. As a result, another minor planet, later designated 176 Iduna, was initially assigned the number 175.
189 Phthia is a bright-coloured, rocky main belt asteroid that was discovered by German-American astronomer Christian Heinrich Friedrich Peters on September 9, 1878, in Clinton, New York, and named after Phthia, a region of ancient Greece.
266 Aline is a fairly large main belt asteroid that was discovered by Johann Palisa on 17 May 1887 in Vienna and is thought to have been named after the daughter of astronomer Edmund Weiss. It is a dark C-type asteroid and is probably composed of primitive carbonaceous material. 266 Aline is orbiting close to a 5:2 mean motion resonance with Jupiter, which is located at 2.824 AU.
289 Nenetta is an A-type asteroid with a diameter of 38 km. It was discovered by Auguste Charlois on 10 March 1890 in Nice, France. The asteroid is orbiting the Sun at a distance of 2.87 AU with an eccentricity (ovalness) of 0.204 and an orbital period of 4.87 yr. The orbital plane is inclined at an angle of 6.7° to the plane of the ecliptic.
333 Badenia is a large background asteroid, approximately 72 kilometers in diameter, located the outer region of the asteroid belt. It was discovered on 22 August 1892, by astronomer Max Wolf at the Heidelberg-Königstuhl State Observatory in southwest Germany. The carbonaceous C-type asteroid has a rotation period of 9.9 hours. It was named after the historical Grand Duchy of Baden that existed until 1918, and where the discovering observatory is located. Badenia was the first asteroid to receive a provisional designation.
400 Ducrosa is a typical Main belt asteroid. It was discovered by Auguste Charlois on 15 March 1895 in Nice, and named for It J. Ducros, a mechanic at the Nice Observatory. This minor planet is orbiting the Sun at a distance of 3.126 AU with a period of 5.527 yr and an orbital eccentricity of 0.117. The orbital plane is inclined at an angle of 10.5° to the plane of the ecliptic.
675 Ludmilla is a minor planet orbiting the Sun. It was named after Mikhail Glinka's opera Ruslan and Lyudmila.
821 Fanny is a dark background asteroid and slow rotator from the central regions of the asteroid belt. It was discovered on 31 March 1916, by German astronomer Max Wolf at the Heidelberg-Königstuhl State Observatory in southwest Germany. The carbonaceous C-type asteroid (Ch) has an exceptionally long rotation period of 236.6 hours and measures approximately 29 kilometers in diameter. Any reference of the asteroid's name to a person is unknown.
174567 Varda (provisional designation 2003 MW12) is a binary trans-Neptunian planetoid of the resonant hot classical population of the Kuiper belt, located in the outermost region of the Solar System. Its moon, Ilmarë, was discovered in 2009.
23135 Pheidas (provisional designation 2000 AN146) is a large Jupiter trojan from the Greek camp, approximately 66 kilometers (41 miles) in diameter. It was discovered on 7 January 2000, by astronomers with the Lincoln Near-Earth Asteroid Research at the Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, in the United States. The dark Jovian asteroid belongs to the 50 largest Jupiter trojans and has a rotation period of 8.7 hours. It was named after the Athenian warrior Pheidas from Greek mythology.